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Experimental results of study of reflected harmonic in silicon
Published in O.A. Aktsipetrov, I.M. Baranova, K.N. Evtyukhov, Second Order Non-linear Optics of Silicon and Silicon Nanostructures, 2018
O.A. Aktsipetrov, I.M. Baranova, K.N. Evtyukhov
In conclusion, we will focus on the work [161] in which, apparently, the authors were first to reported observation of the Pockels effect in silicon MIS structures and the very interesting effect in terms of non-linear optics – optical rectification effect. The Pockels effect is the appearance of induced birefringence in an electric field. The Pockels effect, in contrast to the quadratic Kerr effect, is linear in the applied field, i.e., the change of the components of the tensor of the linear dielectric constant ε↔L(or its inverse optical impermeability tensor η↔=(ε↔L)−1) is directly proportional to the applied field. The Pockels effect is forbidden in the centrosymmetric medium, but may occur in the surface area of silicon when removing the inversion by applying an external electric field. Optical rectification (OR) is the appearance of stationary NP P(0) in propagation of an intense light wave in the medium.
The First Years of Modern Electro‐Optics—A Historical Review
Published in Stoyl P. Stoylov, Maria V. Stoimenova, Molecular and Colloidal Electro-Optics, 2016
The lack of success made me very unhappy and was amplified by the remark of a professor in rheology, who once when visiting my laboratory, told me that in his laboratory people were finding a large Kerr effect on the most classical homopolymer polystyrene (even in molten state). I tried many times to achieve that result by changing the sensitivity of my machine without any success. I was ashamed not to be able to reproduce the rheology professor’s result. Meeting him later in a colloquium, I asked him the details of his experimental method and he told me that it was a mistake and that Kerr effect on polystyrene did not exist (morality: be very cautious about oral results and believe only what has been published). This absence of electrical birefringence on flexible polymers is now easy to understand. The Kerr effect is due to the orientation of the dipoles (permanent or induced) by the electrical field. These dipoles are essentially distributed on the side groups, which mean that if the chain is really flexible, dipoles are oriented without influencing the chain orientation, which is practically not modified. At this time Professor Sadron suggested to me to change my research project and work on classical problems in viscosity with which he was very familiar. However I did refuse and he told me I was taking a risk.
Optical Control Elements
Published in Chunlei Guo, Subhash Chandra Singh, Handbook of Laser Technology and Applications, 2021
Electro-optic modulators using the Kerr effect or the Pockels effect are available, although most modern electro-optic modulators are based on Pockels cells. These modulators exploit the voltage-dependent birefringence induced in some crystalline materials when they are subjected to an external electric field. The Pockels effect has a linear relationship and the electro-optic Kerr effect a quadratic relationship between the indicatrix of the material and the applied electric field. Birefringence is a difference in refractive index dependent on the alignment of the electric field vector with crystal lattice directions.
Accurate second Kerr virial coefficient of rare gases from the state-of-the-art ab initio potentials and (hyper)polarizabilities
Published in Molecular Physics, 2020
The Kerr effect, discovered by John Kerr in 1878 [1], describes the refractive-index change of a material when an electric field is applied. The Kerr electro-optic effect has a fast response to the change of an external electric field and is the basis for electronic controlled optical switches. The Kerr optical effect means that the change of refractive index is proportional to the intensity of light. Its most well-known application nowadays is Kerr-lens modelocking. For an ideal gas, Buckingham et al. [2,3] found that the Kerr constant Km is linearly proportional to the gas density ρ: where the coefficient AK (also called the first Kerr virial coefficient) depends on the atomic second hyperpolarizability γ0. With increasing pressures or densities, the deviations from Eq. (1) can be observed and the terms quadratic, cubic and higher in density contribute to Km(ρ): where BK(T) and CK(T) are the second and third Kerr virial coefficients, respectively and T is the temperature.
Optically induced birefringence in dye-doped blue phase liquid crystals
Published in Liquid Crystals, 2019
Fen-Chi Lin, Hui-Ying Kuo, Shuan-Yu Huang, Tse-Hsien Wu, Jia-De Lin, Chia-Rong Lee
BP is optically isotropic because the orientations of the molecules in BP could be arbitrary direction [2]. With the exertion of electric field, the local LC molecules in BP reorient and thus the BP becomes optically anisotropic. This phenomenon is known as electro-optic Kerr effect since the induced birefringence is proportional to the square of the applied electric field, which is similar to the Kerr effect in nonlinear optics [12]. Electro-optic Kerr effect is the operation mechanism of electrically controllable photonic devices based on BP and thus have been discussed in previous literatures [13–15]. To realise remotely controllable devices, more and more light responsive photonic devices based on dye-doped BP (DDBP) systems have been demonstrated [11,16–18]. The performance in the photo control of DDBP can be improved via adopting specifically synthesised chiral azobenzene derivatives into BP matrix [19]. Literatures also indicate that the uniformity and electro-optical property of BP with photoalignment layers are superior to pure BP [20]. However, only a few papers investigate the phenomenon of photoinduced index change, such as optical Kerr effect, in DDBP and associated mechanisms [21–23].
The influence of diluter system on polymer-stabilised blue-phase liquid crystals
Published in Liquid Crystals, 2018
It is believed that a large Kerr constant is observed for nematic LCs just above the nematic–isotropic phase transition temperature [48]. This is owing to short-range nematic-like order originated from orientational fluctuation in the isotropic liquid. Macroscopically, BPLC is an isotropic Kerr medium when there is no external electric field present. When electric field increases, the BPLC becomes anisotropic along the electric field direction. The refractive index change follows the Kerr effect in the low field region but gradually saturates as the electric field keeps increasing, which can be well explained by an extended Kerr effect [49]. The in the weak field region is related to , wavelength and Kerr constant as shown below: